i am using 15mm tbi motion linear rails on the gantry. I have changed my setup 6 months ago, moved leadscrew too high above the linear rails. I am always pushing my machine to the limits of the spindle (3000mm/min, 2mm wall, 15mm deep, 10mm endmill). I think this was the cause to wear them. I didnt have any issue before the change.

I am changing gantry rails now with 25mm, and putting leadscrew between the linear rails. Considering buying 6.6kw hsk63 spindle.